黄海波，张超，姚炜，雷蕾 

    摘要：为了改善汽油机的NVH性能，对原排气歧管进行了优化设计。对原方案和新方案两种模型利用Fire软件分别进行了数值模拟分析，得到了气体的速度均匀性系数和氧传感器位置的评价指标。结果表明：新方案模型满足设计要求。

    关键词：汽油机；速度均匀性系数；催化转化器

    Abstract: We modified the structure of the exhaust manifold in order to improve the NVH performance, did a simulation analysis to the models of the new and old schemes using the soft of Fire, and obtained the gas velocity uniformity coefficient and the evaluation index of the oxygen sensor position. The conclusion was given that the new model can meet the design demands.

    Key words: Gasoline；Velocity Uniformity Coefficient；Catalytic Converter